The invention relates to an air-induction gasbag-collision-protection system comprising:
a receiving housing, a gasbag casing which is fastened to the receiving housing and is open towards the housing said gasbag casing being folded and disposed in the receiving housing when in an unexpanded state, and
a gas source in the receiving housing for the filling of the gasbag casing and for its unfolding to an expanded state, an intake of air surrounding the receiving housing into the receiving housing and the gasbag casing being facilitated by apertures in a housing wall of the receiving housing, the cross-sections of which apertures are covered by intake flaps, which intake flaps can be opened by underpressure generated in the unfolding of the gasbag casing and by virtue of which an escape of internal gases from the receiving housing through the apertures is prevented.
From European Patent Document EP-A 0 386 365, an aspirator-gasbag (airbag) system is known in which flutter valves, as they are termed, are placed in front of the apertures in the receiving housing and are secured by holders, which flutter valves allow the intake of external air and prevent the escape of gas from the receiving housing, in the opposite direction. The additional flutter valves must be produced as separate parts and fitted to the receiving housing, which, for a gasbag-collision-protection system which is usually only used once and is then completely replaced, leads to an uneconomic increase in, the cost of the protective device.
An object of the invention is to reduce the manufacturing costs of a gasbag-collision-protection system of the generic type.
The object is achieved by providing a system wherein each intake flap is cut into the housing wall as part of the receiving housing and is pivotable in the direction of the housing interior about a lateral edge remaining on the receiving housing.
By virtue of the intake flaps being cut into the housing wall as part of the receiving housing, into the housing wall and being pivotable about a lateral edge remaining on the receiving housing, in the direction of the interior of the housing, an easily realized facility is discovered for adding ambient air from the passenger compartment to the gases for the unfolding of the gasbag, which ambient air pyrotechnically reduces the volume of gas to be generated and thereby reduces the rise in pressure in the passenger compartment as the gasbag is inflated. A complicated valve construction is not necessary for this, since the intake flaps only swivel inwards once the underpressure resulting from the unfolding of the gasbag is sufficiently great.
In order to prevent an escape of gases as the gas source is opened and the therewith associated gas propulsion, on the one hand the material resistance in the swivel axes of the intake flaps can be configured according to requirements by the shape design adopted at this spot and, in addition, the cut edges of the intake flaps can be provided with a slant, by virtue of which the border of the intake flap covers, from the housing interior, the oblique aperture border in the receiving housing, thereby preventing an outward swivel motion.
It may further be provided according to certain preferred embodiments of the invention to dispose a screening plate between a pipe gas generator as the gas source and the intake flaps in the receiving housing, which screening plate prevents the intake flaps from being directly pressurized by gas flowing out of the pipe gas generator. A linear thickening or thinning of the receiving housing in the region of the swivel axis to be formed is particularly simple to realize in the case of a synthetic receiving housing, where these cross-sectional changes to the housing wall can be constructed without any great effort. The possibility of different times of opening and/or opening speeds, matched to the circumstances prevailing in the unfolding, is thus provided for the various intake flaps.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.